Process of producing low-carbon ferro-alloys.



electric furnace, the relative afiinities of the molten alloy of iron, ahighly-positive metal UNITED STATES PATENT OFFICE.

EDGAR F. PRICE, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO ELEOTROMETALLURGICAL COMPANY, OF OHIOAGO ILLINOIS,

CORPORATION OF WEST VIRGINIA.

PROCESS OF PRODUCING LOW-CARBON FERRO-ALLOYS.

Specification of Letters Patent.

Patented May. 5, 11908.

A Applicationfiled September 24, 1907. Serial N 0. 394,254.

To all whom it may concern:

Be it known that I, EDGAR F. PRICE, a citizen of the United States,residing at Niagara Falls, in the county of Niagara and State of NewYork, have invented certain new and useful Improvements in Processesof/Producing Low-Carbon Ferro-Alloys, of which the following is aspecification.

The value of the ferro-alloys commonly employed as a means ofintroducing chromium, vanadium and other metals into special steels, islargely de endent on a low carbon content, and met ods of reductioninvolving the use ofexpensive metallic reducing agents, or giving lowyields, are employed to produce these alloys.

The present process of producing low-carbon ferro-alloys comprises twostages. In the first stage, a hi h-carbon ferro-alloy, for example oneof fiiromium, molybdenum, tungsten, titanium, vanadium or nickel, ischeaply produced by smelting a mixture of an ore of the alloying metal,an excess of carbon and a source of iron. The reduction may be effectedin an ordinary electric furnace having a carbon lining and dependingcarbon electrodes.

In the second stage, the carbon is removed or reduced to a smallercentage by electrically heating the mol fenalloyto a temperature suchthat the affinity of oxygen for the contained carbon is greater than itsaflinity for the chromium or other alloyed metal,- and then subjectingit for a limited period to the'action of air or other oxidizing gas. Inthe ordinary Bessemer process of producin steel, the molten pig-ironcontaining a sma 1 amount of silicon or other highlypositivemetal andcarbon is subjected to the action of air at temperatures such'that theaffinity of oxygen for the silicon or other alloyedpositive-metal isgreater thanits affinity for carbon, so that the removal of the alloyedmetal substantially precedes the removal of carbon. But when thetemperature of a and carbon, is'raised to a definite, oint, dependent onthe particularalloyed metal, a temperature above that employed in theBessemer steel industry or usually roduced by combustion butreadily-obtaina le in an alloyed metal and carbon toward oxygen change,the heat of combination of the carbon and oxygen becomesgreater than theheat of combination of the alloyed metal and oxy gen, and the carbon maythen be largely or substantially eliminated by oxidation before anyconsiderable percentage of the-alloyed metal is removed.

In carrying out the second stage of the process, the high-carbonferro-alloy is heated to the requisite temperature by su porting thebody of the molten alloy in the orm of a ring or closed loop, and makingthis body the secondary of astatic transformer, the rimary of which isfed with an alternating,

ulsatin or intermittent electric current.

ither t e entire mass of alloy to be decarburiz'ed may be comprised inthis ring, or the ring may comprise an are or loop of molten alloy theends of which join the main mass. When the alloy is thus, heated to there uisite high temperature, either in the re uction furnace orin aseparate vessel, it is forced through the alloy or caused to act uponits'surfaoe, as in the present art of bessemerizingpig-iron.

I claim:

1. The process of producing low-carbon ferro-alloys, which consists infirst producing a'ferro-alloy high in carbon, heatingxthe roduct to atemperature such that t e a of oxygen for the contained carbon isgreater than its affinity for the alloyed metal, by constituting a bodyof the molten alloy the secondary of a transformer and su plyingelectric current to'the primary of sai transformer, and subjecting theheated alloy to the action of an oxidizing gas.

2. The process of producing low-carbon ferro-alloys,= which consists inelectrically smelting a compound of the alloying metal, an excess ofcarbon'and a source of iron, heating the product to a temperature suchthat the affinity of oxygen for the contained carbon is greater thanitsaflinity for the alloyed metal, by constitutin a body of the moltenalloy the secondary of a transformer and supplying electric current tothe primary of said transformer, and subjecting the heated alloy to theaction of an oxidizing gas. y

3. The process of producing low-carbon ferrochromium, which consists infirst pro:

by constituting a body of the molten alloy the secondary of atransformer and supplying electric current to the primary of saidtransformer, and subjecting the heated alloy to the action of anoxidizing gas.

4. The process of producing low-carbon ferrochromium, which consists inelectrically smelting a compound of chromium, an excess of carbon and asource of iron, heating the product to a temperature such that theaflinity of oxygen for the contained carbon is greater than its afiinityfor chromium, by

constituting a body of the molten alloy the secondary of a transformerand su plying electric current to the primary of sai transformer, andsubjecting the heated alloy to the action ofan oxidizin gas.

In testimony whereof, %affix my signature in presence of two witnesses.

G. E. Cox, I. R. EDMANDS.

